1. Field of the Invention
This invention relates to improvements in the structure of an image blur correction apparatus carried on an apparatus having an image blur correction function, such as a camera.
2. Related Background Art
Present-day cameras have become automatic in all operations important to photographing, such as exposure determination or focusing and, therefore, the possibility that even a person unskilled in operating a camera will cause a failure in photographing has been drastically reduced.
Also, recently, a system for preventing hand vibration applied to a camera has been studied and the factors for inducing photographers""error in photographing have become almost null. The system for preventing hand vibration will be described briefly here. The hand vibration of a camera during photographing is usually a vibration of 1 Hz to 10 Hz as a frequency. As a basic concept for enabling a photograph free of image blur to be taken, even if such hand vibration is caused at the release point of time of a shutter, the vibration of the camera by the hand vibration must be detected and a correction optical system must be activated in conformity with the detected value of the vibration.
Accordingly, to take a photograph free of image blur even if camera vibration occurs, it becomes necessary to accurately detect the vibration of the camera and to correct the change in an optical axis caused by the hand vibration. Theoretically speaking, the detection of this vibration (camera vibration) can be accomplished by carrying, on the camera, vibration detection means provided with a vibration detection sensor for detecting acceleration, angular acceleration, angular speed, angular displacement, etc., and a calculation portion for suitably calculating the output thereof for the correction of the camera vibration. On the basis of this detected information, a correction optical system for making the photograph optical axis eccentric is driven, and image blur restraint is effected.
Here, the epitome of a vibration preventing system using the vibration detection means will be described with reference to FIG. 10 of the accompanying drawings.
FIG. 10 shows a system for restraining image blur originating from camera pitch vibration 81p and camera yaw vibration 81y indicated by arrow 81.
In FIG. 10, reference numeral 82 designates a lens barrel. Reference characters 83p and 83y denote vibration detection means for detecting camera pitch vibration and yaw vibration, respectively, and their respective vibration detection directions are indicated as 84p and 84y. Reference numeral 85 designates an image blur correction apparatus (86p and 86y denote detection elements for detecting the position of a correction optical system, and 87p and 87y designate coils for giving a thrust force to the correction optical system), and this image blur correction apparatus 85 has a position control loop formed therein, and is driven with the outputs of the vibration detection means 83p and 83y as target values, and assures the stability on the image plane 88.
Also, in the image blur correction apparatus according to the prior art, there have been made countermeasures for damage caused by the disturbance during the carrying of the correction optical system in its non-restrained state by causing the restraining operation to be performed after the termination of hand vibration correction driving or during the consumption of a power source, and a proposition for preventing photographing in the non-restrained state other than during the hand vibration correction driving, or a proposition for supporting the correction optical system by an elastic member, and holding the correction optical system at or about the optical axis during hand vibration correction non-driving.
In the present-day image blur correction apparatus as described above, means for driving the correction optical system, a guide member for making the movement in only the same plane possible, a holding member for holding the correction optical system at or substantially at the center, etc., are indispensable, and depending on the structure thereof, the apparatus has become bulky, and this has hindered the downsizing of an interchangeable lens or the like mounted on an optical apparatus having this apparatus, for example, a camera or the like.
Also, the bulkiness of the image blur correction apparatus has affected the entire optical system and has resulted in the possibility of the degree of freedom being reduced.
It is an object of the present invention to provide an apparatus for achieving the downsizing and electric power saving of an image blur correction apparatus and a camera or an optical apparatus on which the image blur correction apparatus is carried, and preventing the inclination of a correction optical system by a posture difference.
To achieve the above object, in the present invention, there is provided an image blur correction apparatus having a correction optical system for image blur correction held by a supporting member, driving means for driving the correction optical system, a resilient member for holding the correction optical system at or about an optical axis, and a guide member for holding the correction optical system movably along a plane perpendicular to the optical axis, the resilient member and the guide member being disposed in the same plane or different planes orthogonal to the optical axis. Further, the resilient member and the guide member are substantially angularly equally divided into at least three locations and provided radially.